Ref ID : 1325
Stephen J. Perriss, Johanna Laybourn-Parry, and Roger I. Jones; Chlorophyll contents and photosynthetic rates of the freshwater mixotrophic ciliate Strombidium viride (Ciliophora: Oligotrichida). Arch.Hydrobiol. 130(4):473-483, 1994
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The photosynthetic rates and chlorophyll-a contents of Strombidium viride, a chloroplast-retaining mixotrophic ciliate, are reported for individuals collected from Lake Carter, a small productive pond located in northwest England. This species fixed [14]C (added as bicarbonate) at rates between 18 and 54 pgC/cell hr, according to the light intensity used in each incubation. The mean chlorophyll-a content of S. viride was estimated to be 160 pg. The mean cell volume of S. viride individuals was 57.5 µm3. Measurements of the [14]C-uptake rates of whole water samples suggested that the contribution of this species to community primary production in Lake Carter was 0.5% at the time of sampling. The possible advantages and disadvantages of chloropolast-retention to freshwater ciliates are discussed. It is suggested that the augmenting of phagotrophy with photosynthesis becomes a requirement for many strombidiids living in low nutrient environments in order to meet the high metabolic cost associated with maintaining high swimming speeds.